Preheat your smoker to 250°F as per your manufacturer's instructions. I like to use a mix of cherry and apple wood.
With a sharp knife remove the top layer of fat on the pork belly. Score the fat in 1 inch squares. You don’t want to cut all the way through the pork belly, only go around a ¼ inch deep.
In a medium sized bowl mix together cayenne, chilli powder, cumin, garlic, mustard powder, paprika, sugar and salt & pepper.
Dab any excess moisture off the pork belly with a paper towel. Then apply the mustard binder. Then rub the dry rub over the top, bottom and sides of the pork belly. Don’t be scared to get in there with your hands and make sure everything is covered.
Once the smoker is up to temperature smoke the pork belly fat side up until bronzed with smoke. You are looking for an internal temperature of 165°F. This should be around 2 - 3 hours, however, I would advise checking after 2.5 and adjust accordingly.
At 165°F wrap your pork in foil with apple juice
Once the internal temperature reaches 200°F, remove from the smoker, unwrap the foil, and finish under the broiler on maximum heat for 10–15 minutes until the skin blisters and crackles. Watch it constantly — it burns fast
Once skin is crispy (10-15 minutes) remove the piece of pork from the smoker and allow to rest for at least 15-20 minutes